Orientation dependence of spatial memory acquired from auditory experience

The present study investigated whether memory for a room-sized spatial layout learned through auditory localization of sounds exhibits orientation dependence similar to that observed for spatial memory acquired from stationary viewing of the environment. Participants learned spatial layouts by viewing objects or localizing sounds and then performed judgments of relative direction among remembered locations. The results showed that direction judgments following auditory learning were performed most accurately at a particular orientation in the same way as were those following visual learning, indicating that auditorily encoded spatial memory is orientation dependent. In combination with previous findings that spatial memories derived from haptic and proprioceptive experiences are also orientation dependent, the present finding suggests that orientation dependence is a general functional property of human spatial memory independent of learning modality.

Visual and proprioceptive representations in spatial memory

It has been shown that spatial information can be acquired from both visual and nonvisual modalities. The present study explored how spatial information from vision and proprioception was represented in memory, investigating orientation dependence of spatial memories acquired through visual and proprioceptive spatial learning. Experiment 1 examined whether visual learning alone and proprioceptive learning alone yielded orientation-dependent spatial memory. Results showed that spatial memories from both types of learning were orientation dependent. Experiment 2 explored how different orientations of the same environment were represented when they were learned visually and proprioceptively. Results showed that both visually and proprioceptively learned orientations were represented in spatial memory, suggesting that participants established two different reference systems based on each type of learning experience and interpreted the environment in terms of these two reference systems. The results provide some initial clues to how different modalities make unique contributions to spatial representations.

Integrating object locations in the memory representation of a spatial layout

The present study investigated how object locations learned separately are integrated and represented as a single spatial layout in memory. Two experiments were conducted in which participants learned a room-sized spatial layout that was divided into two sets of five objects. Results suggested that integration across sets was performed efficiently when it was done during initial encoding of the environment but entailed cost in accuracy when it was attempted at the time of memory retrieval. These findings suggest that, once formed, spatial representations in memory generally remain independent and integrating them into a single representation requires additional cognitive processes.

Anterior temporal cortex and semantic memory : reconciling findings from neuropsychology and functional imaging

Studies of semantic impairment arising from brain disease suggest that the anterior temporal lobes are critical for semantic abilities in humans; yet activation of these regions is rarely reported in functional imaging studies of healthy controls performing semantic tasks. Here, we combined neuropsychological and PET functional imaging data to show that when healthy subjects identify concepts at a specific level, the regions activated correspond to the site of maximal atrophy in patients with relatively pure semantic impairment. The stimuli were color photographs of common animals or vehicles, and the task was category verification at specific (e.g., robin), intermediate (e.g., bird), or general (e.g., animal) levels. Specific, relative to general, categorization activated the antero-lateral temporal cortices bilaterally, despite matching of these experimental conditions for difficulty. Critically, in patients with atrophy in precisely these areas, the most pronounced deficit was in the retrieval of specific semantic information.

Optimizing I/O cost and managing memory for composition vector method based on correlation matrix calculation in bioinformatics

The generation of a correlation matrix for set of genomic sequences is a common requirement in many bioinformatics problems such as phylogenetic analysis. Each sequence may be millions of bases long and there may be thousands of such sequences which we wish to compare, so not all sequences may fit into main memory at the same time. Each sequence needs to be compared with every other sequence, so we will generally need to page some sequences in and out more than once. In order to minimize execution time we need to minimize this I/O. This paper develops an approach for faster and scalable computing of large-size correlation matrices through the maximal exploitation of available memory and reducing the number of I/O operations. The approach is scalable in the sense that the same algorithms can be executed on different computing platforms with different amounts of memory and can be applied to different bioinformatics problems with different correlation matrix sizes. The significant performance improvement of the approach over previous work is demonstrated through benchmark examples.

The French polisher and the unsentimental interior

In January 2011 a swollen Brisbane River broke its banks flooding riverside houses and buildings. The river’s water spread and rose up through storm water drains inundating some 20 000 houses in low-lying land. As the water receded those residents affected by the floods returned to their homes to assess the damage. While some people breathed a sigh of relief others were devastated by the overwhelming damage to their homes and personal belongings. Over the next few weeks the landscape of Brisbane was altered not merely by the mud and debris left by the torrent of water, but by the piles of domestic contents occupying Brisbane streets. Beds, toys, cabinets, plasterboard, tiles and household furniture lined curbsides waiting for collection. Later they would accumulate in public parks and sports centres to await disposal, momentarily creating an unsettling landscape of discarded domestic interiors. While most houses remained standing the heart breaking repercussions were evident in their interiority. Thousands of volunteers flocked to help those affected by the floods to purge the damage left by the water – removing wall and floor linings, discarding furniture and spoilt belongings. In her paper on Hurricane Katrina, Julieanna Preston wrote, ‘What anthropological evidence would we find as we followed their migration – heaps left by the side of the road, the physical weight overcoming the personal value…’ For many of the post flood restored homes and buildings entire interiors have been replaced, eradicating any trace of the significant event that disturbed them only months earlier. There were artifacts that would have survived the floods - furniture of solid timber – these were discarded and with them the patina that marked an important event in history. The patina is beyond technological reproducibility, and as Walter Benjamin writes, this being the whole premise of genuineness. It is the role of the French Polisher to maintain the true wear of the artefact for it is the patina that is most valuable in its ability to narrate the history of a piece. In 2012 two separate exhibitions in Brisbane will take place to display a selected collection of flood-damaged artefacts. This orchestrated way to commemorate the damage left by floods may be a method to compensate for the haste in which the damage was purged from the city. This need for exhibiting damaged artifacts illustrates Andreas Huyssen’s point that "…today memory is understood as a mode of re-presentation and as belonging to the present." This research looks at the dying trade of the French Polisher through conversations and a visual study of flood damaged furniture. The research also investigates the personal loss of artifacts through intimate stories shared by flood victims. This paper seeks to understand why so much was discarded and celebrate what remains.

The brain-specific microRNA miR-128b regulates the formation of fear-extinction memory

MicroRNAs are small non-coding RNAs that mediate post-transcriptional gene silencing. Fear-extinction learning in C57/Bl6J mice led to increased expression of the brain-specific microRNA miR-128b, which disrupted stability of several plasticity-related target genes and regulated formation of fear-extinction memory. Increased miR-128b activity may therefore facilitate the transition from retrieval of the original fear memory toward the formation of a new fear-extinction memory.

Paradoxical enhancement of fear extinction memory and synaptic plasticity by inhibition of the histone acetyltransferase p300

It is well established that the coordinated regulation of activity-dependent gene expression by the histone acetyltransferase (HAT) family of transcriptional coactivators is crucial for the formation of contextual fear and spatial memory, and for hippocampal synaptic plasticity. However, no studies have examined the role of this epigenetic mechanism within the infralimbic prefrontal cortex (ILPFC), an area of the brain that is essential for the formation and consolidation of fear extinction memory. Here we report that a postextinction training infusion of a combined p300/CBP inhibitor (Lys-CoA-Tat), directly into the ILPFC, enhances fear extinction memory in mice. Our results also demonstrate that the HAT p300 is highly expressed within pyramidal neurons of the ILPFC and that the small-molecule p300-specific inhibitor (C646) infused into the ILPFC immediately after weak extinction training enhances the consolidation of fear extinction memory. C646 infused 6 h after extinction had no effect on fear extinction memory, nor did an immediate postextinction training infusion into the prelimbic prefrontal cortex. Consistent with the behavioral findings, inhibition of p300 activity within the ILPFC facilitated long-term potentiation (LTP) under stimulation conditions that do not evoke long-lasting LTP. These data suggest that one function of p300 activity within the ILPFC is to constrain synaptic plasticity, and that a reduction in the function of this HAT is required for the formation of fear extinction memory.

Toward an object-based semantic memory for long-term operation of mobile service robots

Throughout a lifetime of operation, a mobile service robot needs to acquire, store and update its knowledge of a working environment. This includes the ability to identify and track objects in different places, as well as using this information for interaction with humans. This paper introduces a long-term updating mechanism, inspired by the modal model of human memory, to enable a mobile robot to maintain its knowledge of a changing environment. The memory model is integrated with a hybrid map that represents the global topology and local geometry of the environment, as well as the respective 3D location of objects. We aim to enable the robot to use this knowledge to help humans by suggesting the most likely locations of specific objects in its map. An experiment using omni-directional vision demonstrates the ability to track the movements of several objects in a dynamic environment over an extended period of time.

Nonvolatile multilevel data storage memory device from controlled ambipolar charge trapping mechanism

The capability of storing multi-bit information is one of the most important challenges in memory technologies. An ambipolar polymer which intrinsically has the ability to transport electrons and holes as a semiconducting layer provides an opportunity for the charge trapping layer to trap both electrons and holes efficiently. Here, we achieved large memory window and distinct multilevel data storage by utilizing the phenomena of ambipolar charge trapping mechanism. As fabricated flexible memory devices display five well-defined data levels with good endurance and retention properties showing potential application in printed electronics.

The use of correspondence analysis to compare major and trace elements for provenance studies of iron-age pottery from the Mngeni river area, South Africa

Provenance studies of iron-age pottery specimens originating from the Mngeni river area in South Africa was carried out by applying XRF spectrometry. A total of sixteen major and trace elements were analysed in a batch of 107 potsherds, excavated from four different archaeological sites in the aforementioned area. A multivariate statistical programme Correspondence Analysis was used in this study to obtain the relevant clustering patterns according to the similarity of the elemental distributions. Differences and similarities in the clusters obtained for the majors and trace elements are discussed.

Predicting transactive memory systems in multidisciplinary teams : The interplay between team and professional identities

In explaining how communication quality predicts TMS in multidisciplinary teams, we drew on the social identity approach to investigate the mediating role of team identification and the moderating role of professional identification. Recognizing that professional identification could trigger intergroup biases among professional subgroups, or alternatively, could bring resources to the team, we explored the potential moderating role of professional identification in the relationship between team identification and TMS. Using data collected from 882 healthcare personnel working in 126 multidisciplinary hospital teams, results supported our hypothesis that perceived communication quality predicted TMS through team identification. Furthermore, findings provided support for a resource view of professional subgroup identities with results indicating that high levels of professional identification compensated for low levels of team identification in predicting TMS. We provide recommendations on how social identities may be used to promote TMS in multidisciplinary teams.

The monadic environment : evoking emotion and memory in participatory performance

This practice-led research project examined the audience experience of immersive environments in participatory performance. Drawing upon the work of artist Ilya Kabakov, Gaston Bachelard's Poetics of Space (1964) and Leibniz's theory of the monad, the study investigated how an immersive space can be constructed to evoke emotion and memory recall in participants. The research consisted of two cycles of creative experimentation resulting in the presentation of a final piece entitled Dulcet. The research contributes new terminology to the discourse surrounding the participant experience in immersive environments, specifically space-as-memory, the role of ambiguity in spatial design and the construct of the monadic environment.